1. Technical Field
The present disclosure generally relates to storage systems for data and in particular to improving solid state storage system reliability.
2. Description of the Related Art
As the value and use of information continue to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes, thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.
An information handling system can be configured in several different configurations. The information handling system can range from a single, stand-alone computer system to a distributed, multi-device computer system, to a networked computer system with remote or cloud storage systems. The remote or cloud storage systems can include redundant arrays of independent drives (RAID) that use hard disk drives or solid state storage drives. RAID systems balance the storage of data across the drive in the system to improve performance and reliability. Improvement of the storage system is achieved by balancing write load across the disk drives.
While the load balancing features of RAID storage schemes such as RAID-5 work well for hard disk drives, they cause several disadvantages when used with solid state drives. Non-volatile memory devices such as NAND flash memory devices have a limited number of write or program erase (P/E) cycles to each cell after which the cell is unusable. Over time, the memory cells wear out due to the repeated application of electrical currents causing breakdown of insulating layers within the transistors. Typical NAND flash memory devices can withstand around 100,000 P/E cycles. After the P/E cycle life is exceeded, worn out cells can deteriorate the integrity of the storage causing loss of data. Data written to worn out cells can be lost. Each solid state drive has a maximum number of program/erase cycles called the endurance life. Once the endurance life of the solid state drive is exceeded, data can no longer reliably be written to the drive.
The load balancing features of RAID storage schemes cause the solid state drives in a solid state storage system to wear at the same rate. This lock step wear schedule can cause the solid state drives in a solid state storage system to all approach their endurance life at approximately the same time, leaving the storage system vulnerable to multiple drive failures at the same time. Thus, the present storage systems do not provide adequate protection for the operation of solid state drives.